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Laboratory information systems typically contain hundreds or even thousands of reference limits stratified by sex and age. Since under these conditions a manual plausibility check is hardly feasible, we have developed a simple algorithm that facilitates this check. An open-source R tool is available as a Shiny application at github.com/SandraKla/Zlog_AdRI. Based on the zlog standardization, we can possibly detect critical jumps at the transitions between age groups, regardless of the analytical method or the measuring unit. Its advantage compared to the standard z-value is that means and standard deviations are calculated from the reference limits rather than from the underlying data itself. The purpose of the tool is illustrated by the example of reference intervals of children and adolescents from the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER). The Shiny application identifies the zlog values, lists them in a colored table format and plots them additionally with the specified reference intervals. The algorithm detected several strong and rapid changes in reference intervals from the neonatal period to puberty. Remarkable jumps with absolute zlog values of more than five were seen for 29 out of 192 reference limits (15.1%). This might be attenuated by introducing shorter time periods or mathematical functions of reference limits over age. Age-partitioned reference intervals will remain the standard in laboratory routine for the foreseeable future, and as such, algorithmic approaches like our zlog approach in the presented Shiny application will remain valuable tools for testing their plausibility on a wide scale. [ABSTRACT FROM AUTHOR]

Background: Cancer antigen CA125 is known as a valuable marker for the management of ovarian cancer. Methods: The analytical and clinical performance of the Access OV Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA125 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the OV Monitor ranged between 3.1% and 8.8%, and inter-laboratory reproducibility between 4.7% and 5.0%. Linearity upon dilution showed a mean recovery of 100% (SD+8.1%). Endogenous interferents had no influence on OV Monitor levels (mean recoveries: hemoglobin 107%, bilirubin 103%, triglycerides 103%). There was no high-dose hook effect up to 27,193 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access OV Monitor and Elecsys CA125 (R=0.982, slope=0.921, intercept=+1.951). OV Monitor serum levels were low in healthy individuals (n=267, median=9.7 kU/L, 95th percentile=30.8 kU/L), higher in individuals with various benign diseases (n=549, medians=10.9–16.4 kU/L, 95th percentiles=44.2–355 kU/L) and even higher in individuals suffering from various cancers (n=995, medians=12.4–445 kU/L; 95th percentiles=53.4–4664 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the OV Monitor was found for ovarian cancer [area under the curve (AUC) 0.898]. Results for the reference CA125 assay were comparable (AUC 0.899). Conclusions: The Access OV Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with Elecsys CA125. The best diagnostic accuracy for the OV Monitor was found in ovarian cancer. Our results also suggest a clinical value of the OV Monitor in other cancers. Clin Chem Lab Med 2008;46:588–99. [ABSTRACT FROM AUTHOR]

Children with congenital heart disease (CHD) undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at risk for systemic inflammation leading to endothelial dysfunction associated with increased morbidity. Bioactive adrenomedullin (bio-ADM) is a peptide regulating vascular tone and endothelial permeability. The aim of this study was to evaluate the dynamics of plasma bio-ADM in this patient cohort and its role in capillary leak. Plasma samples from 73 pediatric CHD patients were collected for bio-ADM measurement at five different timepoints (TP) in the pre-, intra-, and post-operative period. The primary endpoint was a net increase in bio-ADM levels after surgery on CPB. Secondary endpoints included association of bio-ADM levels with clinical signs for endothelial dysfunction. Bio-ADM levels increased after surgery on CPB from pre-operative median of 12 pg/mL (IQR [interquartile range] 12.0–14.8 pg/mL) to a maximum post-operative median of 48.8 pg/mL (IQR 34.5–69.6 pg/mL, p<0.001). Bio-ADM concentrations correlated positively with post-operative volume balance, (r=0.341; p=0.005), increased demand for vasoactive medication (duration: r=0.415; p<0.001; quantity: TP3: r=0.415, p<0.001; TP4: r=0.414, p<0.001), and hydrocortisone treatment for vasoplegia (bio-ADM median [IQR]:129.1 [55.4–139.2] pg/mL vs. 37.9 [25.2–64.6] pg/mL; p=0.034). Patients who required pleural effusion drainage revealed higher bio-ADM levels compared to those who did not (median [IQR]: 66.4 [55.4–90.9] pg/mL vs. 40.2 [28.2–57.0] pg/mL; p<0.001). Bio-ADM is elevated in children after cardiac surgery and higher levels correlate with clinical signs of capillary leakage. The peptide should be considered as biomarker for endothelial dysfunction and as potential therapeutic target in this indication. [ABSTRACT FROM AUTHOR]

To evaluate the diagnostic performance of the prostate health index (PHI) and of the percentage of [-2]proPSA (%[-2]proPSA) calculated with total and free PSA from non-Beckman Coulter manufacturers (Roche and Abbott), and compare it with the fully Beckman Coulter [-2]proPSA derivatives. In this study, 237 men (PSA: 2–10 μg/L) scheduled for prostate biopsy were enrolled. %[-2]proPSA and PHI were calculated with total and free PSA from three manufacturers. Beckman Coulter PSA and [-2]proPSA were performed on the Access 2 analyzer (Hybritech calibration). Roche PSA was performed on the cobas e411 and the Abbott PSA on the Architect i2000sr. Statistical analysis was performed, considering prostate cancer (PCa) as the outcome. Univariate analysis showed that all indices were predictors of cancer, irrespective of the manufacturer (p<0.001). The AUC was similar for all manufacturers, both for %[-2]proPSA (Beckman Coulter: 0.756; Roche: 0.770; Abbott: 0.756) and PHI (Beckman Coulter: 0.776; Roche: 0.785; Abbott: 0.778). When considering the cutoffs that allowed 90% sensitivity, [-2]proPSA derivatives calculated with Roche and Abbott PSA had similar specificities and predictive values when compared to Beckman Coulter. The percentage of missed cancers (8–9%) was the same between manufacturers. The percentage of spared biopsies was significantly higher with Roche's PHI (21.0%) and Abbott's PHI (20.6%) than with Beckman Coulter's PHI (17.2%). In the PSA range between 2 and 10 μg/L, [-2]proPSA derivatives maintain their diagnostic performance in PCa detection when calculated with PSA from Roche and Abbott. This can lead to a broader implementation of these indices in clinical laboratories worldwide. [ABSTRACT FROM AUTHOR]

Keywords: evidence based-medicine; reference change value; tumor biomarker EN evidence based-medicine reference change value tumor biomarker 553 555 3 03/11/22 20220301 NES 220301 To the Editor, A word of caution on using biomarker reference change values (RCV) to guide medical decisions: In a recent study from the EFLM working group on biological variation, the biological variation of tumor markers has been investigated and estimates of the within and between subject biological variations were obtained [[1]]. Also, cancer treatment itself has a significant effect on the tumor and therefore tumor biomarker dynamics. [Extracted from the article]

Background: NT-proBNP is one of the most important biomarkers for the diagnosis and risk assessment of heart failure in adults. Age- and gender-independent reference intervals (RIs) have been reported. In contrast, RIs in children are strongly age-dependent, do not exist for all ages and reveal a right-skewed distribution. Accordingly, no common Z-score can be formed and a cross-age interpretive method, so far, is missing. Methods: Within the paper on hand, new evaluation techniques are applied to already published NT-proBNP study results and additionally to newly gained data. Upper limits (ULs), lower limits (LLs) and 50th percentiles are tested for power-like behavior as a function of age using linear regression analysis. Functions for continuous RIs are derived and reference limits are calculated on a per day basis. A corresponding Zlog formula is deduced and its usefulness is stated in two clinical examples. Results: The power-like behavior of NT-proBNP concentration from birth to 18 years is demonstrated. With age in days t and measured NT-proBNP value x in pg/mL, an age-specific Zlog value may directly be calculated using the equation: Zlog NT-proBNP = log x + 0.512 ⋅ log t − 3.417 1.489 + 0.014 ⋅ log t ⋅ 3.92 ${\rm{Zlo}}{{\rm{g}}_{{\rm{NT - proBNP}}}} = {{\log \;x + 0.512 \cdot \log \;t - 3.417} \over {1.489 + 0.014 \cdot \log \;t}} \cdot 3.92$ Conclusions: Using formulas for UL and LL, continuous RIs from 0 to 18 years may be obtained. Continuity corresponds to physiological changes in the body much better than discrete RIs. With the advent of an NT-proBNP-specific Zlog value, a cross-age Z-score equivalent is providing an easy interpretation aid in everyday pediatric practice. This new approach allows to identify clinical worsening much better, sooner and more clearly than previous absolute values. [ABSTRACT FROM AUTHOR]

Background: Cancer antigen CA15-3 antigen is known as a valuable marker for the management of breast cancer. Methods: The analytical and clinical performance of the Access® BR Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA15-3 on the Elecsys® System (Roche Diagnostics). Results: Total imprecision (%CV) of the BR Monitor ranged between 5.5% and 11.7%, and inter-laboratory reproducibility between 3.4% and 5.1%. Linearity upon dilution showed a mean recovery of 98.5% (SD±9.1%). Endogenous interferents had no influence on BR Monitor levels (mean recoveries: hemoglobin 112%, bilirubin 111%, triglycerides 108%). There was no high-dose hook effect up to 13,540 kU/L. Clinical performance investigated in sera from 1811 individuals showed a general correlation between the Access BR Monitor and Elecsys CA15-3 (R=0.797), with a slope of 1.383. CA15-3 serum levels, as measured by the BR Monitor, were low in healthy individuals (n=267, median=11.9 kU/L, 95th percentile=23.5 kU/L), higher in individuals with various benign diseases (n=549, medians=11.3–15.6 kU/L, 95th percentiles=21.6–54.6 kU/L) and even higher in individuals suffering from various cancers (n=995, medians=11.2–22.8 kU/L, 95th percentiles=30.0–429.7 kU/L). Best diagnostic accuracy for cancer detection against the relevant benign control group by the BR Monitor was found for locoregional and metastatic breast cancer, as well as for ovarian cancer [area under the curve (AUC) 0.619, 0.897 and 0.774]. Results for the reference CA15-3 assay were comparable (AUC 0.611, 0.887 and 0.818). Conclusions: The Access BR Monitor provides accurate methodological characteristics and demonstrates an analytical and clinical correlation with Elecsys CA15-3. Best diagnostic accuracy for the BR Monitor was found in breast and ovarian cancer. Our results also suggest a clinical value of the BR Monitor in other cancers. Clin Chem Lab Med 2008;46:612–22. [ABSTRACT FROM AUTHOR]

Background: Gastrointestinal cancer antigen CA19-9 is known as a valuable marker for the management of patients with pancreatic cancer. Methods: The analytical and clinical performance of the Access® GI Monitor assay (Beckman Coulter) was evaluated on the UniCel® DxI 800 Immunoassay System at five different European sites and compared with a reference method, defined as CA19-9 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the GI Monitor ranged between 3.4% and 7.7%, and inter-laboratory reproducibility between 3.6% and 4.0%. Linearity upon dilution showed a mean recovery of 97.4% (SD+7.2%). Endogenous interferents had no influence on GI Monitor levels (mean recoveries: hemoglobin 103%, bilirubin 106%, triglycerides 106%). There was no high-dose hook effect up to 115,000 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access® GI Monitor and Elecsys CA19-9 (R=0.959, slope=1.004, intercept=+0.17). GI Monitor serum levels were low in healthy individuals (n=267, median=6.0 kU/L, 95th percentile=23.1 kU/L), higher in individuals with various benign diseases (n=550, medians=5.8–13.4 kU/L, 95th percentiles=30.1–195.5kU/L) and even higher in individuals suffering from various cancers (n=995, medians=8.4–233.8 kU/L, 95th percentiles=53.7–13,902 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the GI Monitor was found for pancreatic cancer [area under the curve (AUC) 0.83]. Results for the reference CA19-9 assay were comparable (AUC 0.85). Conclusions: The Access® GI Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with the Elecsys CA19-9. The GI Monitor shows the best diagnostic accuracy in pancreatic cancer. Our results also suggest a clinical value of the GI Monitor in other cancers. Clin Chem Lab Med 2008;46:600–11. [ABSTRACT FROM AUTHOR]

Between 1997 and 2000 we investigated in a prospective study the voided urine samples of all consecutive patients undergoing cystoscopy independent from their clinical background (n = 705) with the BTA-TRAK™ assay (Bard Diagnostics, Redmont, USA) detecting a complement factor H-related protein (CFHrP) and the NMP22 assay (Matritech, Newton, USA) measuring a nuclear matrix protein, which is supposed to be specific for bladder cancer. The individuals were divided into three groups concerning the clinical background: 233 patients had urological diseases, 268 patients had urinary bladder cancer and 150 patients had other urological malignancies. Based on the clinical findings we compared our results with well established diagnostic methods for urinary bladder cancer such as cytology and the detection of hematuria. In addition, we investigated urine samples from 30 healthy individuals and 24 patients with urinary tract infection without performing cystoscopy. Following the recommendations of the European Group on Tumor Markers we used 95% specificity for benign urological diseases and urinary tract infections, which resulted in a sensitivity of 17% for active bladder cancer for the BTA-TRAK™ assay and 31% for NMP22. We compared these results with the detection of hematuria (specificity: 72%) and cytology, which had a sensitivity of 64% and 89%, respectively. Subsequently, we calculated sensitivity and specificity for the detection of relapse of the disease. Again using 95% specificity, in this case for patients with recurrent disease the BTA-TRAK™ assay showed 8% sensitivity as compared to 12% for the NMP22 assay. Due to an insufficient specificity and sensitivity, both tests can neither be clinically useful in screening of high risk patients, nor in primary diagnosis of bladder cancer. They cannot replace neither cystoscopy nor cytology. In the follow-up care more investigations may be necessary to prove the benefit of existing diagnostic strategi... [ABSTRACT FROM AUTHOR]

This international multicenter study was designed to evaluate the technical performance of the new double-monoclonal, single-step Elecsys neuron-specific enolase (NSE) enzyme immunoassay (EIA) and to assess its utility as a sensitive and specific test for the diagnosis of small-cell lung cancer (SCLC). Intra- and interassay coefficients of variation, determined in five control or serum specimens in six laboratories, ranged from 0.7 to 5.3 (inter-laboratory median: 1.3%) and from 1.3 to 8.5 (inter-laboratory median: 3.4%), respectively. Laboratory-to-laboratory comparability was excellent with respect to recovery and inter-assay coefficients of variation. The test was linear between 0.0 and 320 ng/ml (highest measured concentration). There was a significant correlation between NSE concentrations measured using the Elecsys NSE and the established Cobas Core NSE EIA II in all subjects (n = 723) and in patients with lung cancer (n = 333). However, NSE concentrations were systematically lower (approximately 9%) with the Elecsys NSE than with the comparison test. Based on a specificity of 95% in comparison with the group suffering from benign lung diseases (n = 183), the cut-off value for the discrimination between malignant and benign conditions was set at 21.6 ng/ml. NSE was raised in 73.4% of SCLC patients (n = 188) and was significantly higher (p < 0.01) in extensive (87.8%) as opposed to limited disease (56.7%). NSE was also elevated in 16.0% of the cases with non-small cell lung cancer (NSCLC, n = 374). It is concluded that the Elecsys NSE EIA is a reliable and accurate diagnostic procedure for the measurement of NSE in serum samples. The special merits of this new assay are the wide measuring range (according to manufacturer's declaration up to 370 ng/ml) and a short incubation time of 18 min. [ABSTRACT FROM AUTHOR]